page 455, compared with The Ruby Programming Language by David Flanagan & Yukihiro Matsumoto, O’Reilly 2008, there is some discrepancy at the beginning of the table. And defined? is added.
page 455, compared with The Ruby Programming Language by David Flanagan & Yukihiro Matsumoto, O’Reilly 2008, there is some discrepancy at the beginning of the table. And defined? is added.